Summary: Journal of Heredity
doi:10.1093/jhered/esq009
Ó The American Genetic Association. 2010. All rights reserved.
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Complementation, genetic conflict, and
the evolution of sex and recombination
MARCO ARCHETTI
From the Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge,
MA 02138-2902.
Address correspondence to M. Archetti at the address above, e-mail: archetti@fas.harvard.edu.
Abstract
The existence of sexual reproduction is difficult to explain because the 2-fold cost of meiosis requires a compensatory 2-fold
advantage that is difficult to prove. Here, I show that asexual reproduction has a short-term disadvantage due to the loss of
complementation of recessive deleterious mutations, which can overcome the 2-fold cost of meiosis in one or few
generations. This complementation hypothesis can also explain why most asexual species are polyploid, why only certain
types of asexual reproduction exist, why meiosis is not one-step, and the origin of amphimixis. I also show that the
promotion of variation by recombination is not necessary to explain the evolution of amphimixis. Instead, recombination
can be the result of an intragenomic conflict between alleles that induce the initiation of crossing over and alleles that evolve
to resist that initiation. Thus recombination does not require any advantage at the individual or population level.
Key words: amphimixis, apomixis, automixis, endomitosis, asexual reproduction, complementation, deleterious mutations, gene conversion,